1. Field of the Invention
The present invention relates to containers; and more specifically, to a plastic, stackable container comprising a lid and a box, wherein the stacking strength of the container, especially of the lid, is considerably increased over that of existing containers.
2. Discussion of the Prior Art
Presently known stackable plastic containers comprising load carrying lids are not suitable for heavy payloads due to their structural design.
Reinforcing means such as webs, ribs, beams, girders and the like, can be placed on or formed as an integral part of the lid. It is, however, impracticable to arrange such reinforcements on the lower horizontal surfaces around the border of the lid because of small contact area between said horizontal surfaces and the upper rim of the box. This results in strength and stability problems that are especially pronounced in the four corners of the lid where up to 80% of the strain caused by weights placed on top of the lid is absorbed. The strain related diagonally inwards and/or downwards directed forces will inevitably bend the inner area of the lid downwards and the four corners upwards, whereby the lid finally will be squeezed down into the box. Such an impact on a lid will pose an obvious and very high risk of lopsidednesses, which finally will overturn a stack of containers.